Where to Place the Jack?

[McRuby]

When changing a tire, the jack should be placed under the chassis, near the wheel, on the raised position. The operation of the jack should not be rushed; it should rise rhythmically and uniformly, and descend slowly. When using multiple jacks simultaneously, operate them synchronously. After using the jack, conduct a thorough inspection to check the hydraulic pressure and potential hazards, perform maintenance, and store it in an appropriate place. Jacks can be categorized by structural features into three types: rack jacks, screw jacks, and hydraulic jacks. Below are detailed introductions: 1. Screw Jack: The screw jack's threads do not have a self-locking function and are equipped with a brake. Releasing the brake allows the load to descend quickly, reducing return time, but this type of jack is more complex in construction. Screw jacks can support heavy loads for extended periods, with a maximum lifting capacity of up to 100t, making them widely applicable. When fitted with a horizontal screw at the bottom, they can also enable small-distance horizontal movement of the load. 2. Hydraulic Jack: Used in hydraulic transmission systems as an intermediate medium, it plays a role in transmitting and converting energy. Additionally, it serves functions such as lubrication, corrosion prevention, cooling, and flushing of components within the hydraulic system. 3. Electric Jack: The electric jack is equipped with a pressure-retaining device to prevent overpressure. If overpressure occurs, the jack may not return to a certain position. Its special structure provides dual protection for the jack. When fitted with a diving device, it can achieve high travel with low height.

[VanPatrick]

Last week while helping my neighbor change a tire, I noticed many people jack up the wrong spot and damage the undercarriage. Actually, you can see arrow markings or small raised triangles beneath the doors—follow this line toward the undercarriage to feel for a palm-sized reinforced steel plate, which is the proper jacking point. For my SUV, it needs to be lifted on the inner side beam of the rocker panel, while sedans usually have their support points hidden behind plastic side skirts. Remember never to jack up the fuel tank, exhaust pipe, or suspension control arms—last time at the repair shop, we saw a case where someone cracked a fuel tank shell, spilling gasoline everywhere. The safest method is to mark a red circle with a marker on the rocker panel; when changing tires at night, just feel for the edges.

[VanJesse]

When teaching my daughter how to change a tire, I realized the jacking points are quite particular, varying significantly between different cars. Lift the trunk mat to check the owner's manual—manufacturers usually illustrate the load-bearing points. My habit is to wear gloves and feel along the chassis frame rails, avoiding fuel lines until I locate the hard triangular weld seams. I've seen fellow car owners place hydraulic jacks on plastic fender liners, only to have the entire side skirt fall off, costing an extra 700+ yuan to fix. Older German cars often have notched metal protrusions, while American pickups require jacking at the reinforced frame holes. If all else fails, inspect the chassis below the doors—those areas with thickened layers and anti-rust paint are foolproof spots.

[McAngelo]

Last time I had a flat tire on the national highway, I truly understood the depth of knowledge about car jacks. Lifting at the wrong spot can cause minor body deformation at best, or lead to dangerous slippage at worst. The key is to locate the intersection points of the longitudinal reinforcement ribs on the chassis. Japanese cars often use stamped concave grooves as support points. Remember to clear ground debris before lifting, and use a pry bar to confirm you're on solid metal. My domestic car has blue paint markings underneath, while Korean models often weld coin-sized protrusions on inner door sills. Don't believe online advice about lifting from suspension control arms - a friend cracked his aluminum alloy arm and paid over 2,000 yuan for repairs. For EVs, maintain at least 20cm clearance from the centrally-mounted battery pack in the floor panel.

[LaArianna]

Twenty Years of Mechanic Experience Summary: Find the right fulcrum and kneel down to observe first. There is usually a triangular reinforcement plate under the chassis near the driver's door, and most vehicle models have a cast support platform within fifteen centimeters of the tire. For SUVs, jack at the square hole of the second cross member of the frame; for MPVs, lift the rear floor to find the reinforced longitudinal beam. Stop and check after lifting two centimeters—plastic deformation sounds indicate the wrong jacking point. European cars often use recessed U-shaped channels, while American cars commonly feature protruding riveted blocks. When unsure, align the jack with the center of the brake disc and vertically locate the chassis load-bearing area for maximum safety.

[SanIsaac]

A Painful Lesson from Changing Tires on a Rainy Night: Jack Placement Affects Lifeline. Modern vehicles have yellow adhesive strips marking the jack points beneath the door sills, while older models require feeling for the thickest sections at the four corners of the undercarriage. The lifting height should not exceed 1.5 times the tire's ground clearance—I once jacked too aggressively, causing frame distortion and an $800 repair for misaligned rear doors. When underbody armor obscures jack points, use your phone to photograph and identify the edges of cast iron blocks underneath. Remember three key principles: avoid areas with hoses or wiring, steer clear of the fuel tank, and ensure the jack point is parallel to the tire plane. Finally, wedge the spare tire as a safety buffer before crawling underneath.